Such impact protection devices serve as improvement of the passive safety of vehicles, air bag modules having been introduced as standard successively for the driver, where they are housed in the steering wheel, for the second front passenger, where they are housed in the instrument panel, as well as side air bags housed in the doors or seats, respectively and now form part of the basic equipment of almost all modern vehicles. For each vehicle there is a requirement for one to four or even more air bag modules so that the number of manufactured air bags exceeds by far the number of the corresponding vehicles produced. It is, therefore, understandable that efforts are being made to improve the air bag modules as regards manufacturing expenditure, weight, disposal, assembling expenditure etc.
For large scale manufacture of air bag modules, the air bag is usually made up of two circular material blanks which are joined to each other at their rims, one of them having a central intake throat for the inflation gases, the rim being normally clamped between an air bag holding plate and a carrier component of the air bag module. This way of air bag attachment has proved successful over time, but it is also relatively expensive. The air bag holding plate must be inserted through the intake throat and then fixed in relation to the intake throat within the air bag. It must have no sharp edges, to prevent the material from being torn in case the air bag is activated. Furthermore the clamping action around the inlet throat must be applied with a certain minimum force in all places to prevent the material from slipping out at some points in case the air bag is activated whereby is impaired the functionality of the air bag. In order to achieve a sufficiently strong clamping action, the clamping area must be of a certain width, whereby are implied limitations as to the installation and folding possibilities of the air bag.